The torsional vibrations in crankshaftings of high speed Diesel engines become more excessive with the increase of engine power. So it is necessary to improve accuracy in the calculation of torsional vibration amplitude especially resonant amplitude. It is usual to carry out harmonic analysis of resultant torque and estimate the resonant amplitude of each order vibration. On the other hand, it is not easy to calculate accurately resultant amplitude by taking the phase difference between each order vibration into consideration and summing up each order amplitude gained by the above-mentioned calculation. So in the present paper, authors try to calculate directly resultant amplitude by using a step by step transition matrix method. The simulation results for torsional vibrations of high speed Diesel engines are compared with similar results obtained by the conventional method and it is shown that transition matrix solutions are more accurate. At the same time, this paper refers to new experiments in searching for engine damping needed by the simulation of torsional vibration. The obtained results are following. 1) Engine damping ratio in small-sized high speed in-line Diesel engines is approximately 0.03-0.04. 2) Engine damping capacity is subject to the influence of piston rings especially oil rings, but is not influenced by engine speed.

  • Corporate Authors:

    Marine Engineering Society in Japan

    Osaka Building, 1-2-2 Uchisaiwai-Cho, Chiyoda-Ku
    Tokyo 100,   Japan 
  • Authors:
    • Seki, T
  • Publication Date: 1977

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  • Accession Number: 00163064
  • Record Type: Publication
  • Source Agency: Marine Engineering Society in Japan, Bulletin of
  • Report/Paper Numbers: Quarterly
  • Files: TRIS
  • Created Date: Sep 28 1977 12:00AM